Q5 of 112 Page 150

Find the area of the quadrilateral whose vertices are

(–4, 5), (0, 7), (5, – 5) and (–4, – 2)

We must take all the vertices in counter clock wise direction otherwise it will give solution in negative.


So, from the figure we assume that


A (x1, y1) = (5, –5)


B (x2, y2) = (0, 7)


C (x3, y3) = (–4, 5)


D (x4, y4) = (–4, –2)



The area of the quadrilateral is {(x1–x3)(y2–y4) – (x2–x4)(y1–y3)}


= {(5–(–4))(7–(–2)) –(–5–5)(0–(–4))}


= {81+40} = 60.5 Sq. units


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